Camera app stays black/doesn't react after update to Android 9

What happened?

I updated my Fairphone 2 on Android 9. Afterwards, the camera screen stayed black when I wanted to take a picture. I already cleared the data stored in the camera app and the cache and restarted the phone. This brought no change.

Workaround/solution

Wiping cache and data of the Media storage process/app. You can find it by going to Settings > Apps > See all apps > Three dots > Show system > Media storage.

Once there, first try:
App-Info -> Storage -> Clear cache

If this does not work, try:
App Info -> Storage -> Clear storage